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value_context.hpp
1 // Copyright 2014 MongoDB Inc.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #pragma once
16 
17 #include <bsoncxx/builder/core.hpp>
18 #include <bsoncxx/builder/stream/array_context.hpp>
19 #include <bsoncxx/builder/stream/closed_context.hpp>
20 #include <bsoncxx/builder/stream/helpers.hpp>
21 #include <bsoncxx/stdx/type_traits.hpp>
22 
23 #include <bsoncxx/config/prelude.hpp>
24 
25 namespace bsoncxx {
26 inline namespace v_noabi {
27 namespace builder {
28 namespace stream {
29 
47 template <class base>
49  public:
56  BSONCXX_INLINE value_context(core* core) : _core(core) {}
57 
65  template <class T>
66  BSONCXX_INLINE detail::requires_not_t<base, detail::is_invocable<T, single_context>> //
67  operator<<(T&& t) {
68  _core->append(std::forward<T>(t));
69  return unwrap();
70  }
71 
79  template <typename T>
80  BSONCXX_INLINE detail::requires_t<base, detail::is_invocable<T, single_context>> //
81  operator<<(T&& func) {
82  detail::invoke(std::forward<T>(func), *this);
83  return unwrap();
84  }
85 
91  BSONCXX_INLINE key_context<base> operator<<(const open_document_type) {
92  _core->open_document();
93  return wrap_document();
94  }
95 
101  BSONCXX_INLINE array_context<base> operator<<(const open_array_type) {
102  _core->open_array();
103  return wrap_array();
104  }
105 
111  operator single_context();
112 
113 #if !defined(_MSC_VER) && !defined(__INTEL_COMPILER)
114  // TODO(MSVC): Causes an ICE under VS2015U1
115  static_assert(
116  std::is_same<value_context, decltype(std::declval<value_context>() << 1 << "str")>::value,
117  "value_context must be templatized on a key_context");
118 #endif
119 
120  private:
121  BSONCXX_INLINE base unwrap() {
122  return base(_core);
123  }
124 
125  BSONCXX_INLINE array_context<base> wrap_array() {
126  return array_context<base>(_core);
127  }
128 
129  BSONCXX_INLINE key_context<base> wrap_document() {
130  return key_context<base>(_core);
131  }
132 
133  core* _core;
134 };
135 
136 } // namespace stream
137 } // namespace builder
138 } // namespace v_noabi
139 } // namespace bsoncxx
140 
141 #include <bsoncxx/config/postlude.hpp>
A low-level interface for constructing BSON documents and arrays.
Definition: core.hpp:43
core & append(const types::b_double &value)
Appends a BSON double.
core & open_array()
Opens a sub-array within this BSON datum.
core & open_document()
Opens a sub-document within this BSON datum.
A stream context which expects a value, which can later be followed by more key/value pairs.
Definition: value_context.hpp:48
detail::requires_not_t< base, detail::is_invocable< T, single_context > > operator<<(T &&t)
<< operator for accepting a real value and appending it to the core builder.
Definition: value_context.hpp:67
value_context(core *core)
Create a value_context given a core builder.
Definition: value_context.hpp:56
The top-level namespace for bsoncxx library entities.
Definition: element.hpp:24